JP6865074B2 - Antenna device and electronic device equipped with an antenna device - Google Patents

Description

The present invention relates to an antenna device having a plurality of antenna elements corresponding to different frequency bands and an electronic device including such an antenna device.

According to the White Paper on Traffic Safety, the absolute value of the number of traffic accidents has been declining in recent years, but it is pointed out that the percentage of people walking is the highest when looking at the breakdown. In order to improve the safety for such pedestrians, it is being researched and developed to use an inter-vehicle communication system of ITS (Intelligent Transport System), which is a safe driving support wireless system.

The pedestrian-to-vehicle communication device used in the pedestrian-to-vehicle communication system acquires information (current position, traveling direction, moving speed, etc.) of a moving body (pedestrian, vehicle) possessing the pedestrian-to-vehicle communication device, and broadcasts its own information. Send with. As a result, the pedestrian-vehicle communication device can prevent a traffic accident based on the above-mentioned information received from another pedestrian-vehicle-to-vehicle communication device and the above-mentioned information by itself.

It is conceivable that a mobile terminal such as a smartphone has the function of an inter-vehicle communication device. In that case, the mobile terminal supports a frequency band for communication with a mobile base station (that is, for a cellular system). Two antennas are provided, one is an antenna and the other is an antenna corresponding to the frequency band for ITS. When a plurality of antennas are provided in the mobile terminal in this way, it is preferable to weaken the coupling between these antennas (that is, improve the isolation between the antennas) and suppress the interference between the antennas.

In Patent Document 1, in order to provide an antenna device that realizes a high isolation effect and an electronic device provided with this antenna device, the antenna device is arranged substantially parallel to the grounding portion of the electronic device, and the grounding portion is interposed via a grounding element. The first and second antenna grounding portions connected to the antenna are arranged close to each other within a predetermined distance along the side of the antenna grounding portion, and the frequency bands to be transmitted or received are set to be substantially the same. The first antenna unit includes a first feeding point arranged in the vicinity of the side of the grounding portion for an antenna, an intermediate portion formed by at least one diffraction, and one end thereof. The first feeding element connected to the feeding point of 1 and the other end being opened, and one end connected to the grounding portion for an antenna and the other end being opened to supply electricity to the first feeding element. A second antenna unit is provided with a first non-feeding element that operates in combination with the antenna, and the second antenna unit is arranged at a position near the side of the grounding portion for the antenna, away from the first feeding point. A second feeding element in which the feeding point and the middle portion are formed at least once, one end is connected to the second feeding point and the other end is open, and one end is a grounding portion for an antenna. The second non-feeding element is connected to the antenna and the other end is opened, and the second non-feeding element is electrically coupled to the second feeding element to operate and is also electrically coupled to the first non-feeding element. An antenna device including the above is disclosed. In this antenna device, the distance between the grounding position of the first non-feeding element and the grounding position of the second non-feeding element is set to be approximately 1/20 or less of the wavelength corresponding to the frequency band. ing. Further, the length from the tip of the first non-feeding element to the tip of the second non-feeding element via the side of the grounding portion for the antenna is approximately 1/2 of the wavelength corresponding to the frequency band. Is set to.

Patent Document 2 discloses an antenna device in which mutual interference between antennas is reduced to improve isolation characteristics, and an electronic device provided with the antenna device. In this antenna device, a first power feeding terminal is provided near the corner of the grounding pattern on the antenna board on which the grounding pattern is formed, and a second power feeding terminal is provided at a position corresponding to an intermediate portion of the grounding pattern on the antenna board. A terminal is provided. The distance between the first and second feeding terminals is set within a distance of approximately 1/4 wavelength or less of the wavelength corresponding to the preset resonance frequency. One end of a first antenna having a first band including the resonance frequency as a communication band is connected to the first power feeding terminal. Further, one end of a second antenna having a second band including at least the resonance frequency of the first antenna as a communication band is connected to the second feeding terminal. These first and second antennas have portions parallel to the grounding pattern and are arranged so that these parallel portions face the same direction. Further, between the first antenna and the second antenna, a first protruding portion is provided so as to protrude from the ground pattern of the antenna substrate. The first protruding portion has a function of reducing the amount of high-frequency current flowing into each other's feeding terminals between the first and second feeding terminals.

Patent Document 3 is built in the mobile terminal in order to provide an antenna device and a mobile terminal capable of improving the antenna correlation coefficient between the first and second antennas (that is, increasing the isolation between the antennas). A first antenna provided at one end of the board for receiving radio waves, a second antenna provided at the other end of the board for transmitting and receiving radio waves, and a second antenna provided at the one end side of the board to supply power to the first antenna. An antenna device including a first power feeding means for performing power supply and a second power feeding means provided on the other end side of the board for supplying power to the second antenna, and the board is provided with the first power feeding means and the second power feeding means. A conductor member that extends parallel to the line connecting the means, one end is connected to the ground of the substrate at the substantially center of the first power feeding means and the second power feeding means, and the other end is released in the vicinity of the first feeding means. An antenna device characterized by being provided is disclosed. The substrate is a GND substrate whose one side is configured as GND. The conductor member generates an anti-phase current with respect to the current on the substrate flowing in the linear direction connecting the first and second feeding means. An inductor for adjusting the frequency of resonance generated by the conductor member is provided at the connection portion of the conductor member with the substrate. The inductor is frequency-adjusted so that the resonance frequency is near the transmission band of the second antenna.

Japanese Patent No. 5076019 Japanese Patent No. 5162012 JP-A-2015-307241

In the antenna device described in Patent Document 1, the radiation characteristics (directivity, polarization characteristics, etc.) of the first and second antenna units whose frequency bands are set to be substantially the same by the first and second non-feeding elements. ) However, there is a problem that it changes significantly as compared with the case where there is no non-feeding element.

In the antenna device described in Patent Document 2, the protruding portion protruding from the ground pattern of the antenna substrate between the first antenna and the second antenna is not long enough to resonate at the frequencies corresponding to these antennas. There is a problem that the effect of improving isolation is small.

In the antenna device described in Patent Document 3, the antenna device extends parallel to the line connecting the first feeding means and the second feeding means, and one end thereof is substantially at the center of the first feeding means and the second feeding means on the ground of the substrate. A conductor member (non-feeding element) that is connected and whose other end is released in the vicinity of the first feeding means is provided, whereby the reverse of the current on the substrate flowing in the linear direction connecting the first and second feeding means is provided. It generates a phase current and suppresses the current flowing in the line direction connecting the first and second feeding means, which leads to deterioration of the antenna correlation coefficient between the first and second antennas. However, the linear conductor member described in Patent Document 3 has a problem that the current on the substrate cannot be sufficiently suppressed and the effect of improving the antenna correlation coefficient (that is, improving the isolation) is small.

The present invention has a first antenna element used in the first frequency band and a second antenna element used in a second frequency band different from the first frequency band, and the first and second antenna elements are used. Provided are an antenna device in which the isolation between antenna elements in a second frequency band is improved without significantly changing the radiation characteristics in each corresponding frequency band of the antenna element, and an electronic device provided with such an antenna device. The main purpose is to do.

The antenna device of the present invention is electrically connected to the ground conductor, the first and second feeding points arranged apart from each other on the ground conductor or in the vicinity of the ground conductor, and the first feeding point. The first antenna element used in the first frequency band and the second antenna element electrically connected to the second feeding point and used in a second frequency band different from the first frequency band. The antenna element is composed of a first end portion electrically connected to the ground conductor, which is composed of a conductive member arranged apart from the surface of the ground conductor and extending along the surface of the ground conductor, and an open first end portion. The distance from the connection point between the first end portion of the non-feeding element and the ground conductor to the first feeding point is from the connection point. It is smaller than the distance to the second feeding point, and the electric length of the non-feeding element is set to a length at which the non-feeding element resonates in the second frequency band.

Further, the electronic device of the present invention is connected to the antenna device to the first and second feeding points of the antenna device via the first and second feeding lines, and is connected to the outside via the antenna device. It is equipped with a wireless communication unit for communication.

According to the present invention, it has a first antenna element used in the first frequency band and a second antenna element used in a second frequency band different from the first frequency band, and the first and first antenna elements are used. An antenna device in which the isolation between the antenna elements in the second frequency band is improved without significantly changing the radiation characteristics in the corresponding frequency bands of the two antenna elements, and an electronic device provided with such an antenna device. Is provided.

A block diagram showing a schematic configuration of an electronic device provided with an antenna device according to the first embodiment. Schematic diagram showing the frequency band of the first antenna element and the frequency band of the second antenna element Top view showing the antenna device which concerns on 1st Embodiment Perspective view of the antenna device shown in FIG. The figure which shows the isolation characteristic between the antenna elements in the antenna device of 1st Embodiment in comparison with the comparative example. The antenna efficiency of the first antenna element in the antenna device of the first embodiment is shown in comparison with a comparative example (an antenna device having the same configuration as the antenna device of the first embodiment except that a non-feeding element is not provided). Figure The figure which shows the antenna efficiency of the 2nd antenna element in the antenna device of 1st Embodiment in comparison with the comparative example. Top view showing the current distribution when power is supplied to the first antenna element at a frequency within the second frequency band in the conventional antenna device. The plan view which shows the current distribution when the 1st antenna element is fed with the frequency within the 2nd frequency band in the antenna device of 1st Embodiment. Top view showing the antenna device which concerns on 2nd Embodiment Perspective view of the antenna device shown in FIG. Explanatory drawing which shows a plurality of frequency channels of a 2.4 GHz band in which the antenna device which concerns on 3rd Embodiment is used. Schematic diagram showing the configuration of the main part of the antenna device according to the third embodiment. Top view showing the antenna device which concerns on 4th Embodiment

The antenna device according to the first invention made to solve the above problems includes a ground conductor and first and second feeding points arranged on the ground conductor or in the vicinity of the ground conductor so as to be separated from each other. The first antenna element used in the first frequency band electrically connected to the first feeding point and the first frequency band electrically connected to the second feeding point. It consists of a second antenna element used in a second frequency band different from the above, and a conductive member arranged apart from the surface of the ground conductor and extending along the surface of the ground conductor, and is electrically connected to the ground conductor. The first end portion, the open second end portion, the first portion extending from the first end portion in a direction away from the surface of the ground conductor, and the first portion on the side away from the first end portion. A second portion extending from the end of one portion along the surface of the ground conductor, and an end of the second portion on the side away from the first portion, the ground conductor in a direction away from the first antenna element. The distance from the connection point between the first end portion of the non-feeding element and the ground conductor to the first feeding point. Is smaller than the distance from the connection point to the second feeding point, and the electric length of the non-feeding element is set to a length at which the non-feeding element resonates in the second frequency band.

According to this configuration, the distance from the connection point between the first end portion of the non-feeding element and the ground conductor to the first feeding point of the first antenna element is the second antenna element from the connection point. It is smaller than the distance to the feeding point of 2, and the electric length of the non-feeding element is set to the length at which the non-feeding element resonates in the second frequency band, so that the frequency is within the second frequency band. When the first antenna element is fed, the first antenna element and the non-feeding element are electromagnetically strongly coupled, and the current is concentrated on the non-feeding element and the portion of the ground conductor facing the non-feeding element. As a result, the current distributed on the second antenna element is greatly reduced as compared with the case where the non-feeding element is not provided. That is, the isolation between the first antenna element and the second antenna element in the second frequency band is improved. Further, the non-feeding element extends along the surface of the ground conductor and does not have a portion protruding from the ground conductor. Therefore, an extremely narrow resonance characteristic of only the second frequency band is realized, and the radiation characteristic of the first antenna element in the first frequency band (as compared with the case where the non-feeding element is not provided). Directivity, polarization characteristics, etc.) do not change significantly. Further, since it is loosely coupled to the second antenna element, the radiation characteristics of the second antenna element in the second frequency band do not change significantly. Therefore, according to the first invention, it has a first antenna element used in the first frequency band and a second antenna element used in a second frequency band different from the first frequency band. Provided is an antenna device in which the isolation between antenna elements in the second frequency band is improved without significantly changing the radiation characteristics in the corresponding frequency bands of the first and second antenna elements.

Further, in the second invention, the electric length of the non-feeding element is set to a length of approximately 1/4 of the wavelength corresponding to the representative frequency of the second frequency band.

According to this configuration, the length of the non-feeding element can be shortened, the non-feeding element can easily resonate in the second frequency band, and the isolation between the antenna elements in the second frequency band can be improved.

Further, in the third invention, the bandwidth of the second frequency band is narrower than the bandwidth of the first frequency band.

According to this configuration, the resonance bandwidth of the non-feeding element that resonates in the second frequency band is narrowed. Therefore, the non-feeding element is provided while improving the isolation between the antenna elements in the second frequency band. It is possible to effectively prevent a decrease in antenna efficiency in each frequency band of the first antenna element and the second antenna element.

Further, in the fourth invention, the ground conductor has a first side and a second side extending from the first side in a direction intersecting with the first side, and the first side is described. The antenna element is provided in the vicinity of the first side of the ground conductor, and the non-feeding element has a portion extending in a direction intersecting the second side of the ground conductor.

According to this configuration, the resonance bandwidth of the non-feeding element is narrowed, and the electromagnetic coupling between the non-feeding element and the first antenna element is further strengthened, so that the electromagnetic coupling between the first antenna element and the second antenna element is further strengthened. Isolation is further improved.

Further, in the fifth invention, the first antenna element and the second antenna element are provided in the vicinity, and the third portion is in a direction away from the first antenna element and the second antenna element. It extends along the surface of the ground conductor .

According to this configuration, when the first antenna element is fed with a frequency within the second frequency band, the current distributed in the non-feeding element and the portion of the ground conductor facing the non-feeding element is near the second side. Since it gathers in a portion away from the second antenna element provided in the above, it is difficult for the current to flow to the second antenna element. Therefore, the current generated on the second antenna element when the power is supplied to the first antenna element is reduced. That is, the isolation between the first antenna element and the second antenna element is improved.

Further, in the sixth invention, the first antenna element is also used in the third frequency band, and the second frequency band is located between the first frequency band and the third frequency band. ..

According to this configuration, since the operating frequency band of the first antenna element includes the second frequency band, interference between the antenna elements is likely to occur in the second frequency band, but even in such a case, the second frequency band is likely to occur. Interference between antenna elements can be effectively suppressed in the frequency band.

Further, in the seventh invention, the transmission power of the radio wave radiated from the first antenna element is larger than the transmission power of the radio wave radiated from the second antenna element.

According to this configuration, the radio wave having a large transmission power radiated from the first antenna element tends to adversely affect the wireless communication executed by using the second antenna element, but the first antenna element and the non-feeding element By electromagnetically strongly coupling with and from, the isolation between the first antenna element and the second antenna element can be improved, and such an influence can be reduced.

Further, in the eighth invention, the first end portion of the non-feeding element is connected to the ground conductor via a reactance element.

According to this configuration, the electric length of the non-feeding element can be set to an appropriate length without changing the physical length of the non-feeding element, and the resonance frequency of the non-feeding element can be matched with a desired frequency with high accuracy.

Further, in the ninth invention, the reactance element is a variable reactance element.

According to this configuration, when a plurality of frequency bands (frequency channels) are dynamically switched and used as a second frequency band, the reactorance value of the variable reactorance element is controlled according to the frequency channel used. Therefore, the resonance frequency of the non-feeding element can be matched to the frequency channel used, and the isolation between the antenna elements can be improved more effectively.

Further, in the tenth invention, the antenna device is composed of a conductive member arranged apart from the surface of the ground conductor and extending along the surface of the ground conductor, and is electrically connected to the ground conductor. It further has a second non-feeding element having an end and an open second end, and is a connection point between the first end of the second non-feeding element and the ground conductor. The distance from the second connection point to the second feeding point is smaller than the distance from the second connecting point to the first feeding point, and the electric length of the second non-feeding element is the second. The non-feeding element is set to a length that resonates in the first frequency band.

According to this configuration, when the second non-feeding element feeds the second antenna element at a frequency within the first frequency band, the second non-feeding element electromagnetically strongly couples to the second antenna element to form a ground conductor. It functions to reduce the current generated in the first antenna element and improve the isolation between the antenna elements in the first frequency band.

Further, the electronic device according to the eleventh invention is electrically connected to the antenna device and the first and second feeding points of the antenna device via the first and second feeding lines, and the antenna. It is provided with a wireless communication unit that communicates with the outside via a device.

According to this configuration, it has a first antenna element used in the first frequency band and a second antenna element used in a second frequency band different from the first frequency band, and has first and second antenna elements. It is possible to provide an electronic device provided with an antenna device having improved isolation between antenna elements in the second frequency band without significantly changing the radiation characteristics in each corresponding frequency band of the antenna elements.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment)
FIG. 1 is a block diagram showing a schematic configuration of an electronic device including the antenna device according to the first embodiment. The electronic device 1 shown in FIG. 1 is, for example, a smartphone or a tablet terminal. As shown in FIG. 1, the electronic device 1 includes an input unit 2 for inputting a user's instruction, an output unit 3 for outputting information such as an image and sound, and a memory 4 for storing a program and data. , A controller (processor) 5 that operates based on a program stored in the memory 4 and processes an operation signal input from the input unit 2 and controls the output unit 3, and an antenna device under the control of the controller 5. It has a wireless communication unit 7 that performs wireless communication with the outside via 6. The input unit 2 includes, for example, a touch panel and a microphone. The output unit 3 includes, for example, a liquid crystal display and a speaker.

The antenna device 6 electrically connects to the wireless communication unit 7 via the first antenna element 10 electrically connected to the wireless communication unit 7 via the first feeder line 8 and the wireless communication unit 7 via the second feeder line 9. It has a second antenna element 11 connected to it. The connection point between the first feed line 8 and the first antenna element 10 is the first feed point 12, and the connection point between the second feeder 9 and the second antenna element 11 is the second. It is a feeding point 13. The first antenna element 10 conforms to the frequency band for communication with a mobile base station (not shown) (that is, for a cellular system), and the second antenna element 11 has a frequency band for ITS. Conforms to.

As shown in FIG. 2, in the present embodiment, the frequency band for the cellular system in which the first antenna element 10 is used is the band 28B of the LTE (Long Term Evolution) standard, and the transmission band is the first of 718 to 748 MHz. It includes a frequency band and a third frequency band of 773 to 803 MHz as a reception band. That is, the frequency band for the cellular system includes two frequency bands separated from each other. The frequency band for ITS in which the second antenna element 11 is used comprises a second frequency band of 755 to 765 MHz. That is, in the present embodiment, the second frequency band is located between the first frequency band and the third frequency band, and is adjacent to each of the first and third frequency bands. Further, the bandwidth of the second frequency band (10 MHz) is narrower than the bandwidth of each of the first frequency band and the third frequency band (30 MHz).

In this way, when the first and second antenna elements 10 and 11 corresponding to different adjacent frequency bands are provided in the same electronic device 1, interference between the antenna elements 10 and 11 occurs unless any measures are taken. .. In particular, the first antenna element 10 corresponding to the first and third frequency bands separated from each other and the second antenna element corresponding to the second frequency band located between the first and third frequency bands. When the eleven is provided in the same electronic device 1, the second frequency band is included in the operating frequency band of the first antenna element, so that the radiation efficiency of the first antenna element is inevitably in the second frequency band. It becomes high and interference between the antenna elements 10 and 11 is likely to occur. Further, usually, the transmission power of the radio wave radiated from the first antenna element 10 for the cellular system is larger than the transmission power of the radio wave radiated from the second antenna element 11 for the ITS. In such a case, the radio waves radiated from the first antenna element 10 are likely to adversely affect the wireless communication executed by using the second antenna element 11. Therefore, as described below, the antenna device 6 of the first embodiment has a configuration for enhancing the isolation between the first antenna element 10 and the second antenna element 11 in the second frequency band. In particular, it has a configuration for reducing the influence on the second antenna element when the power is supplied to the first antenna element 10.

Hereinafter, the configuration of the antenna device 6 will be described in detail. FIG. 3 is a plan view showing the antenna device 6 according to the first embodiment, and FIG. 4 is a perspective view of the antenna device 6 shown in FIG.

As shown in FIGS. 3 and 4, the antenna device 6 has a rectangular ground conductor (also referred to as a main plate) 21 having a flat surface provided on the first surface of the substrate 20 mainly made of an insulator. There is. The first antenna element 10 is arranged in the vicinity of the lower side 22 of the ground conductor 21 (an example of the "first side"), and the second antenna element 11 is the upper side 23 ("the first side" facing the lower side 22 of the ground conductor 21. It is arranged in the vicinity of "an example of" 3 sides "). The first antenna element 10 and the second antenna element 11 are composed of inverted L antennas having lengths corresponding to the respective frequency bands, and extend along the corresponding sides 22 and 23 of the ground conductor 21. Have. The grounding conductor 21 is made of, for example, a copper foil or a grounding pattern printed on the substrate 20. The ground conductor 21 does not necessarily have to be provided on the substrate 20, and may be provided, for example, in the housing of the electronic device 1.

Although not shown, wiring is printed on the second surface of the substrate 20 opposite to the first surface. That is, in the present embodiment, the substrate 20 is configured as a printed wiring board. The circuit modules and circuit elements constituting the memory 4, the controller 5, the wireless communication unit 7, and the like shown in FIG. 1 are mounted on the second surface of the substrate 20. The wireless communication unit 7 is connected to the first and second antenna elements 10 and 11 by the first and second feeder lines 8 and 9 on the second surface side of the substrate 20.

As shown in FIG. 3, in the present embodiment, the first feeding point 12 is located on the ground conductor 21 near the left end of the lower side 22 of the ground conductor 21 (that is, overlaps with the ground conductor 21 in a plan view). ing). Further, the second feeding point 13 is located on the ground conductor 21 near the left end of the upper side 23 of the ground conductor 21 (that is, overlaps with the ground conductor 21 in a plan view). As a result, the first feeding point 12 and the second feeding point 13 are separated from each other and are located on the ground conductor 21. The first feeding point 12 and the second feeding point 13 do not necessarily have to be located on the grounding conductor 21, and are arranged in the vicinity of the grounding conductor 21 so as not to overlap the grounding conductor 21 in a plan view. May be good. Further, in FIG. 4, the symbols indicating the feeding points 12 and 13 are omitted in order to clearly indicate the shapes of the antenna elements 10 and 11.

The antenna device 6 has a conductive member 30 that is arranged apart from the surface of the ground conductor 21 and extends along the surface of the ground conductor 21 (preferably parallel to the surface of the ground conductor 21). One end (first end) 31 of the conductive member 30 is electrically connected to the ground conductor 21, and the other end (second end) 32 is an open end not connected to the ground conductor 21. That is, the conductive member 30 constitutes a non-feeding element. The first end 31 of the conductive member 30 may be mechanically connected to the grounding conductor 21 with, for example, a conductive adhesive, or may simply be in contact with the grounding conductor 21.

The connection point 40 between the first end 31 of the non-feeding element (conductive member) 30 and the grounding conductor 21 extends in the direction intersecting the lower side 22 of the grounding conductor 21, and the left side 24 (connecting the lower side 22 and the upper side 23). (Example) of the "second side"), it is arranged at a position closer to the first feeding point 12 than the second feeding point 13. In other words, the distance D1 from the connection point 40 to the first feeding point 12 is smaller than the distance D2 from the connection point 40 to the second feeding point 13.

The non-feeding element 30 is made of a long plate-shaped member, and is bent at the first bent portion 33 and the second bent portion 34. The non-feeding element 30 includes a first portion 35 extending from the first end portion 31 (that is, the connection point 40) to the first bent portion 33 in a direction away from the surface of the ground conductor 21, and a first bent portion 33 (that is, the first bent portion 33 (that is, the connection point 40). That is, the second portion extending from the end portion of the first portion 35 on the side away from the connection point 40) to the second bent portion 34 along the surface of the ground conductor 21 in a direction perpendicular to the left side 24 of the ground conductor 21. 36 and the ground conductor 21 from the second bent portion 34 (that is, the end of the second portion 36 on the side away from the first portion 35) to the second end 32 in the direction toward the lower side 22 of the ground conductor 21. It has a third portion 37 extending along the surface.

It can also be said that the second portion 36 extends toward the inside of the ground conductor 21 in a direction away from the left side 24 of the ground conductor 21. As a result, the open second end 32 of the non-feeding element 30 is located closer to the lower side 22 of the ground conductor than the first end 31 (that is, the connection point 40). Further, the second portion 36 of the non-feeding element 30 extends substantially parallel to the portion of the first antenna element 10 extending along the lower side 22 of the ground conductor 21.

The length from the first end 31 to the second end 32 of the non-feeding element 30 is a wavelength corresponding to the representative frequency of the second frequency band (for example, the center frequency (760 MHz in the example shown in FIG. 2)). It is set to be approximately 1/4 (about 98.6 mm when the representative frequency is 760 MHz). Therefore, the electrical length of the non-feeding element 30 is approximately 1/4 of the wavelength corresponding to the representative frequency of the second frequency band. As a result, the non-feeding element 30 resonates in the second frequency band. If the frequency is within the second frequency band, it may be a frequency other than the center frequency.

Further, in order to make the length of the non-feeding element 30 as small as possible and to facilitate the resonance of the non-feeding element 30 in the second frequency band, the length of the non-feeding element 30 is set to the representative frequency of the second frequency band. It is preferable that the length is approximately 1/4 of the corresponding wavelength, but if space can be secured, the length of the non-feeding element 30 is set to another length such as approximately 1/2 of the wavelength corresponding to the representative frequency of the second frequency band. It may be the case.

Further, even if the physical length of the non-feeding element 30 is the same, the non-feeding element 30 may be affected by a member (for example, a resin housing (chassis) of the electronic device 1) arranged around the non-feeding element 30. Since the electric length can change, as will be described later, by loading a reactance element between the first end portion 31 and the ground conductor 21, the electric length of the non-feeding element 30 corresponds to the representative frequency of the second frequency band. It may be adjusted according to the individual environment so as to be as close as possible to 1/4 of the reactance.

Further, in the present embodiment, the distance from the surface of the ground conductor 21 of the second portion 36 and the third portion 37 of the non-feeding element 30 (that is, the length H of the first portion 35 of the non-feeding element 30) is about. The width W1 of the second portion 36 is 5 mm, the width W1 of the second portion 36 is about 2 mm, and the width W2 of the third portion 37 is about 5 mm. Appropriately set to obtain. In order to obtain a narrow resonance bandwidth, the closer to the first end 31 (connection point 40), the narrower the width, and the closer to the second end 32, the wider the width. That is, in order to obtain a narrow resonance bandwidth, it is preferable to make the width W2 of the third portion 37 larger than the width W1 of the second portion 36. For example, the width W1 of the second portion 36 is set to 0. It may be about 5 mm. Further, the smaller the distance from the surface of the ground conductor 21 of the second portion 36 and the third portion 37 of the non-feeding element 30 (that is, the length H of the first portion 35 of the non-feeding element 30), the more no feeding is performed. The resonance bandwidth of the element 30 tends to be narrowed.

The non-feeding element 30 configured as described above is attached and held inside a resin housing (chassis) of an electronic device such as a smartphone, for example.

FIG. 5 shows that the isolation characteristics between the antenna elements in the antenna device 6 of the first embodiment are the same as those of the antenna device 6 of the first embodiment except that the non-feeding element 30 is not provided. It is a figure which shows in comparison with the apparatus). In FIG. 5, S21 is the coupling coefficient of the second antenna element 11 with respect to the first antenna element 10, and the smaller the value of the coupling coefficient S21, the better the isolation. FIG. 5 shows the frequency characteristics of the coupling coefficient S21 for each of the comparative example (dotted line) and the first embodiment (solid line). As shown in FIG. 5, in the antenna device 6 of the first embodiment, the coupling coefficient S21 in the second frequency band is reduced by 6 to 23 dB as compared with the comparative example. That is, the isolation between the antenna elements 10 and 11 is significantly improved.

FIG. 6 is a diagram showing the antenna efficiency of the first antenna element 10 in the antenna device 6 of the first embodiment in comparison with the comparative example. In FIG. 6, the antenna efficiency of the comparative example is shown by a dotted line, and the antenna efficiency of the first embodiment is shown by a solid line. As shown in FIG. 6, in the antenna device 6 of the first embodiment, although the antenna efficiency of the first antenna element 10 is lower than that of the comparative example in the second frequency band, the first In the first and third frequency bands, which are the operating frequency bands of the antenna element 10, the same or improved as in the comparative example.

FIG. 7 is a diagram showing the antenna efficiency of the second antenna element 11 in the antenna device 6 of the first embodiment in comparison with the comparative example. In FIG. 7, the antenna efficiency of the comparative example is shown by a dotted line, and the antenna efficiency of the first embodiment is shown by a solid line. As shown in FIG. 7, in the antenna device 6 of the first embodiment, the antenna efficiency of the second antenna element 11 is slightly lower than that of the comparative example in the third frequency band, but the second one. In the second frequency band, which is the operating frequency band of the antenna element 11, the antenna element 11 is improved by 1 to 1.5 dB from the comparative example.

As described above, in the antenna device 6 of the first embodiment, the second antenna element 10 and the second antenna element 11 are likely to interfere with each other while improving the antenna efficiency in each operating frequency band. The isolation between the first antenna element 10 and the second antenna element 11 in the frequency band can be significantly improved.

FIG. 8 is a plan view showing a current distribution when power is supplied to the first antenna element 10 at a frequency within the second frequency band (760 MHz in this example) in the conventional antenna device, and FIG. 9 is a plan view showing the first FIG. 5 is a plan view showing a current distribution when power is supplied to the first antenna element 10 at a frequency within the second frequency band in the antenna device 6 of the embodiment.

As shown in FIG. 8, in the conventional antenna device in which the non-feeding element 30 is not provided, when the first antenna element 10 is fed at a frequency within the second frequency band, the first antenna element is supplied. The antenna current of 10 flows through the ground conductor 21 to the second antenna element 11 particularly along the left side 24 of the ground conductor 21, and the current is distributed to the second antenna element 11.

On the other hand, in the antenna device 6 of the first embodiment, as shown in FIG. 9, when power is supplied to the first antenna element 10 at a frequency within the second frequency band (760 MHz in this example), no power is supplied. The current concentrates on the element 30 and the portion of the non-feeding element 30 of the ground conductor 21 facing the element 30. At this time, the directions of the current flowing through the non-feeding element 30 and the current flowing through the portion of the ground conductor 21 facing the non-feeding element 30 are opposite to each other. As a result of the current concentrating on the non-feeding element 30 and the portion of the ground conductor 21 facing the non-feeding element 30, the current distributed on the second antenna element 11 is significantly reduced as compared with the comparative example shown in FIG. To. That is, in the antenna device 6 of the first embodiment, as shown in FIG. 5, the electromagnetic coupling between the first and second antenna elements 10 and 11 is reduced in the second frequency band as compared with the comparative example. , Isolation is improved.

As described above, when the first antenna element 10 is fed with a frequency within the second frequency band in the antenna device 6 of the present embodiment, the non-feeding element 30 and the portion of the ground conductor 21 facing the non-feeding element 30 are formed. The current is concentrated in (1) because the electric length of the non-feeding element 30 is approximately 1/4 of the representative frequency of the second frequency band, the non-feeding element 30 resonates in the second frequency band. And (2) the connection point 40 between the non-feeding element 30 and the ground conductor 21 is the first for the first antenna element 10 rather than the second feeding point 13 for the second antenna element 11. This is because the first antenna element 10 and the non-feeding element 30 are electromagnetically strongly coupled in the second frequency band because they are arranged close to the feeding point 12. When the connection point 40 is brought closer to the first feeding point 12, the resonance bandwidth of the non-feeding element 30 tends to be widened. Therefore, the connection point 40 is separated from the first feeding point 12 by a predetermined distance. It is preferable to have.

Further, the non-feeding element 30 extends along the surface of the ground conductor 21 and does not have a portion protruding from the ground conductor 21 in a plan view. As a result, the resonance of the non-feeding element 30 becomes a resonance due to the mirror image effect with the ground conductor. Therefore, in the antenna device 6 of the first embodiment, the resonance characteristic of the non-feeding element 30 having an extremely narrow band of substantially only the second frequency band is realized, as compared with the case where the non-feeding element 30 is not provided. , The radiation characteristics (directivity, polarization characteristics, etc.) of the first antenna element in the first frequency band do not change significantly. Further, since the non-feeding element 30 and the second antenna element 11 are loosely coupled, the radiation characteristics of the second antenna element 11 do not change significantly. As an example, the resonance characteristic of the non-feeding element 30 is the dimension of each part of the non-feeding element 30 (that is, the distance from the surface of the ground conductor 21 of the second portion 36 and the third portion 37 of the non-feeding element 30 (that is,). By appropriately setting the length H) of the first portion 35 of the non-feeding element 30), the value of the coupling coefficient S21 when the non-feeding element 30 shown by the solid line in FIG. 5 is provided is shown in FIG. The width between frequencies that are improved by 6 dB (that is, lowered by 6 dB) compared to the value of the coupling coefficient S21 when the non-feeding element 30 shown by the broken line is not provided is adjusted so as to roughly match the second frequency band. It's okay.

Further, in the antenna device 6 of the first embodiment, the non-feeding element 30 has a second portion 36 extending along the surface of the ground conductor 21 in a direction perpendicular to the left side 24 of the ground conductor 21. That is, when the second portion 36 of the non-feeding element 30 feeds the first antenna element 10 at a frequency within the second frequency band when the non-feeding element 30 is not provided as shown in FIG. , It extends to the inner part of the ground conductor 21 where almost no current is distributed. As a result, the resonance bandwidth of the non-feeding element 30 in the second frequency band is narrowed, and the electromagnetic coupling between the non-feeding element 30 and the first antenna element 10 is further strengthened. In order to obtain the effect of narrowing the resonance bandwidth of the non-feeding element 30 and strengthening the electromagnetic coupling between the non-feeding element 30 and the first antenna element 10, the second portion 36 of the non-feeding element 30 is the ground conductor 21. It does not necessarily have to extend in a direction perpendicular to the left side 24, and may extend in a direction substantially perpendicular to the left side 24. Further, the second portion 36 of the non-feeding element 30 may extend obliquely with respect to the left side 24 of the ground conductor 21. That is, the second portion 36 of the non-feeding element 30 may extend in a direction intersecting the left side 24 of the ground conductor 21.

Further, in the antenna device 6 of the first embodiment, the second antenna element 11 is provided in the vicinity of the upper side 23 of the ground conductor 21, and the open second end 32 of the non-feeding element 30 is the first end 31. It is located closer to the lower side 22 of the ground conductor 21 than the connection point 40 (that is, the first end portion 31) between the ground conductor 21 and the ground conductor 21. Therefore, as shown in FIG. 9, when the first antenna element 10 is fed with a frequency within the second frequency band, the non-feeding element 30 and the portion of the ground conductor 21 facing the non-feeding element 30 Since the distributed current collects in a portion away from the second antenna element 11 provided near the upper side 23, it is difficult for the distributed current to flow to the second antenna element 11. Therefore, the current generated on the second antenna element 11 when the power is supplied to the first antenna element 10 is reduced. That is, the isolation between the first antenna element 10 and the second antenna element 11 is improved.

Further, as described above, the non-feeding element 30 of the antenna device 6 of the first embodiment is separated from the first portion 35 extending from the first end portion 31 in the direction away from the surface of the ground conductor 21 and the first end portion 31. Separated from the second portion 36 extending along the surface of the ground conductor 21 in a direction substantially perpendicular to the left side 24 of the ground conductor 21 from the end of the first portion 35 on the side of the ground, and the first portion 35 of the second portion 36. It has a third portion 37 extending along the surface of the ground conductor 21 in a direction from the end on the side toward the first side 22. As a result, as described above, the resonance bandwidth of the non-feeding element 30 is narrowed by the second portion 36 extending along the surface of the ground conductor 21 in a direction substantially perpendicular to the left side 24 of the ground conductor 21, and the non-feeding element 30 And the electromagnetic coupling between the first antenna element 10 and the first antenna element 10 are further strengthened. Further, it is possible to easily realize a configuration in which the second end portion 32 of the non-feeding element 30 is located closer to the first side 22 of the ground conductor 21 than the first end portion 31.

Further, as described above, in the antenna device 6 of the first embodiment, the connection point 40 between the first end portion 31 of the non-feeding element 30 and the ground conductor 21 is the left side connecting the lower side 22 and the upper side 23 of the ground conductor 21. It is arranged on 24. As shown in FIG. 8, when the non-feeding element 30 is not provided, when the first antenna element 10 is fed with a frequency within the second frequency band, the antenna current of the first antenna element 10 is increased. It flows to the second antenna element 11 along the left side 24 of the ground conductor 21, and the current is also distributed on the second antenna element 11. Since the connection point 40 between the first end 31 of the non-feeding element 30 and the ground conductor 21 is arranged on the left side 24, the current flowing to the second antenna element 11 along the left side 24 of the ground conductor 21. Is cut off, the current distributed on the second antenna element 11 can be reduced, and the isolation can be improved.

Further, as described above, in the antenna device 6 of the first embodiment, the length H of the first portion 35 of the non-feeding element 30, the width W1 of the second portion 36, the width W2 of the third portion 37, and the like are appropriately adjusted. By doing so, the resonance bandwidth of the non-feeding element 30 substantially matches the second frequency band. As a result, it is possible to prevent a decrease in antenna efficiency in each operating frequency band of the first antenna element 10 and the second antenna element 11 due to the provision of the non-feeding element 30. Rather, due to the decrease in the electromagnetic coupling between the antenna elements 10 and 11, as shown in FIGS. 6 and 7, the antenna efficiency in each operating frequency band of the first antenna element 10 and the second antenna element 11 is increased. This is improved as compared with the case where the non-feeding element 30 is not provided. If the resonance bandwidth of the non-feeding element 30 is significantly narrower than that of the second frequency band (that is, the resonance is sharp), a portion where isolation is not improved occurs in the second frequency band. On the contrary, when the resonance bandwidth of the non-feeding element 30 is significantly wider than the second frequency band, there is a portion where the antenna efficiency is lowered in each frequency band of the first antenna element 10 and the second antenna element 11. obtain. Therefore, as described above, it is preferable that the resonance bandwidth of the non-feeding element 30 substantially coincides with the second frequency band.

(Second Embodiment)
Next, the second embodiment of the present invention will be described. 10 is a plan view showing the antenna device 6a according to the second embodiment, and FIG. 11 is a perspective view of the antenna device 6a shown in FIG. FIG. 12 is an explanatory diagram showing a plurality of frequency channels in the 2.4 GHz band in which the antenna device 6a according to the second embodiment is used. It should be noted that the points not particularly mentioned in the description of the second embodiment are the same as those of the first embodiment described above.

As shown in FIGS. 10 and 11, the antenna device 6a of the second embodiment both has first and second antenna elements 110 and 111 arranged in the vicinity of the upper side 23 of the ground conductor 21 ( In the second embodiment, the upper side 23 corresponds to the "first side"). Each of the first and second antenna elements 110 and 111 has a portion extending along the upper side 23. The first feeding point 112 for the first antenna element 110 is arranged near the right end of the upper side of the ground conductor 21, and the second feeding point 113 for the second antenna element 111 is the left end of the upper side 23 of the ground conductor 21. It is located in the vicinity. As a result, the first feeding point 112 and the second feeding point 113 are arranged apart from each other in the direction along the upper side 23 of the ground conductor 21.

As shown in FIG. 12, in the second embodiment, the 2.4 GHz industrial science medical band (ISM band) is divided into a plurality of frequency bands (referred to as frequency channels) each having a bandwidth of 5 MHz. In FIG. 12, the upper frequency indicates the center frequency of each frequency channel. In this embodiment, the first antenna element 110 and the second antenna element 111 are used for different frequency channels. In this case, the frequency channel in which the first antenna element 110 is used corresponds to the first frequency band in the present invention, and the frequency channel in which the second antenna element 111 is used corresponds to the second frequency band in the present invention. obtain. In the second embodiment, since the first antenna element 110 and the second antenna element 111 both correspond to the 2.4 GHz ISM band (that is, they are assigned to the first antenna element 110 and the second antenna element 111). The first antenna element 110 and the second antenna element 111 have the same shape (length), although they are bilaterally symmetric (because the influence on the physical length of these antenna elements is small due to the difference in the frequency channels to be generated). ..

Similar to the first embodiment, the antenna device 6a of the second embodiment has a conductive member 130 which is arranged apart from the surface of the ground conductor 21 and extends along the surface of the ground conductor 21. One end (first end) 131 of the conductive member 130 is electrically connected to the ground conductor 21, and the other end (second end) 132 is an open end not connected to the ground conductor 21. That is, the conductive member 130 constitutes a non-feeding element.

The connection point 140 between the first end 131 of the non-feeding element (conductive member) 130 and the grounding conductor 21 is located below the upper side 23 of the grounding conductor 21 at the first feeding point 112 rather than the second feeding point 113. It is located close to each other. That is, even in the second embodiment, the distance D1 from the connection point 140 to the first feeding point 112 is smaller than the distance D2 from the connection point 140 to the second feeding point 113.

The non-feeding element 130 of the second embodiment is also made of a long plate-shaped member, and is bent at the first bent portion 133 and the second bent portion 134. The non-feeding element 130 includes a first portion 135 extending from the first end portion 131 (that is, the connection point 140) to the first bent portion 133 in a direction away from the surface of the ground conductor 21, and a first bent portion 133 (that is, the first bent portion 133 (that is, the connection point 140). That is, the second portion extending from the end portion of the first portion 135 on the side away from the connection point 140) to the second bent portion 134 along the surface of the ground conductor 21 in a direction perpendicular to the left side 24 of the ground conductor 21. A ground conductor in a direction away from the upper side 23 of the ground conductor 21 from 136 and the second bent portion 134 (that is, the end of the second portion 136 on the side not connected to the first portion 135) to the second end 132. It has a third portion 137 extending along the surface of 21. As a result, the open second end 132 of the non-feeding element 130 is located away from the upper side 23 of the first end 131 (that is, the connection point 140). Further, the second portion 136 of the non-feeding element 130 extends substantially parallel to the extending portion of the first antenna element 110 extending along the upper side 23 of the ground conductor 21.

In the second embodiment, the length from the first end 131 to the second end 132 of the non-feeding element 130 is the representative frequency (second frequency band) of the frequency channel (second frequency band) in which the second antenna element 111 is used. For example, it is set to be approximately 1/4 of the wavelength corresponding to (center frequency). Therefore, the electric length of the non-feeding element 130 is approximately 1/4 of the wavelength corresponding to the representative frequency of the second frequency band. As a result, the non-feeding element 130 resonates in the second frequency band. Further, as in the first embodiment, the dimensions of each part of the non-feeding element 130 of the second embodiment are such that the resonance bandwidth of the non-feeding element 130 is the bandwidth of the second frequency band (5 MHz in this example). It is set to almost match.

Similarly to the antenna device 6 of the first embodiment, the antenna device 6a of the second embodiment having the above-described configuration also uses the second antenna element 111 having the electric length of (1) the non-feeding element 130. The non-feeding element 130 resonates in the second frequency band because it is approximately 1/4 of the representative frequency of the second frequency band (frequency channel), and (2) the non-feeding element 130 and the ground conductor 21 The feature is that the connection point 140 between the antennas is arranged closer to the first feeding point 112 for the first antenna element 110 than the second feeding point 113 for the second antenna element 111. Therefore, the isolation between the antenna elements in the second frequency band is improved in the same manner as described above for the first embodiment.

Further, the non-feeding element 130 extends along the surface of the ground conductor 21 and does not have a portion protruding from the ground conductor 21 in a plan view. Therefore, the radiation characteristics (directivity, polarization characteristics, etc.) of the first and second antenna elements 110 and 111 do not change significantly as compared with the case where the non-feeding element 130 is not provided.

Further, also in the antenna device 6a of the second embodiment, the non-feeding element 130 has a second portion 136 extending along the surface of the ground conductor 21 in a direction perpendicular to the left side 24 of the ground conductor 21. As a result, the resonance bandwidth of the non-feeding element 130 in the second frequency band is narrowed, and the electromagnetic coupling between the non-feeding element 130 and the first antenna element 110 is further strengthened, and as a result, the first antenna element The isolation between the 110 and the second antenna element 111 is improved. The second portion 136 of the non-feeding element 130 does not necessarily have to extend in a direction perpendicular to the left side 24 of the ground conductor 21, and may extend in a direction substantially perpendicular to the ground conductor 21. Further, the second portion 136 of the non-feeding element 130 may extend obliquely with respect to the left side 24 of the ground conductor 21. That is, the second portion 136 of the non-feeding element 130 may extend in a direction intersecting the left side 24 of the ground conductor 21.

Further, in the antenna device 6a of the second embodiment, the open second end 132 of the non-feeding element 130 is located farther from the upper side 23 than the first end 131 (that is, the connection point 140). .. Therefore, as in the first embodiment, when the first antenna element 110 is fed with a frequency within the second frequency band, it is distributed in the portion of the non-feeding element 130 and the ground conductor 21 facing the non-feeding element 130. The current collects in a portion away from the second antenna element 11 provided in the vicinity of the upper side 23, and does not easily flow to the second antenna element 11. Therefore, the current generated on the second antenna element 111 when the power is supplied to the first antenna element 110 is reduced. That is, the isolation between the first antenna element 110 and the second antenna element 111 is improved.

Further, in the antenna device 6a of the second embodiment, the non-feeding element 130 has a first portion 135 extending from the first end 131 in a direction away from the surface of the ground conductor 21, and a side away from the first end 131. The second portion 136 extending from the end of the first portion 135 along the surface of the ground conductor 21 in a direction substantially perpendicular to the left side 24 of the ground conductor 21, and the side of the second portion 136 away from the first portion 135. It has a third portion 137 extending along the surface of the ground conductor 21 in a direction away from the upper side 23 from the end. According to this, the resonance bandwidth of the non-feeding element 130 is narrowed by the second portion 136 extending along the surface of the ground conductor 21 in a direction substantially perpendicular to the left side 24 of the ground conductor 21, and the non-feeding element 130 and the first The electromagnetic coupling of the antenna element 110 is further strengthened. Further, it is possible to easily realize a configuration in which the second end 132 of the non-feeding element 130 is located farther from the upper side 23 of the ground conductor 21 than the first end 131.

(Third Embodiment)
Next, the third embodiment will be described. FIG. 13 is a schematic view showing the configuration of a main part of the antenna device 6b according to the third embodiment. It should be noted that the points not particularly mentioned in the description of the third embodiment are the same as those of the first embodiment or the second embodiment.

In the second embodiment, an example is shown in which the 2.4 GHz ISM band is divided into a plurality of frequency channels and used. In this case, the controller 5 of the electronic device 1 (see FIG. 1) may control the wireless communication unit 7 to dynamically assign these plurality of frequency channels to the first antenna element 110 and the second antenna element 111. it can. At that time, the controller 5 controls the wireless communication unit 7 so that the same frequency channel is not assigned to the first antenna element 110 and the second antenna element 111 by the carrier sense function or the like. In this way, when a plurality of frequency channels are dynamically used, for example, in the second embodiment, the desired resonance frequency of the non-feeding element 130, that is, the desired electricity, is determined according to the frequency channel assigned to the second antenna element 111. The length will change.

As shown in FIG. 13, the antenna device 6b of the third embodiment has a variable reactance unit 250 between the non-feeding element 230 and the ground conductor 21. In FIG. 13, the first and second antenna elements are not shown. The variable reactance unit 250 includes a first fixed capacitance element Cs and a variable capacitance element Cv connected in series, and a second fixed capacitance element connected in parallel to the first fixed capacitance element Cs and the variable capacitance element Cv. Has Cp. The capacitance of the first fixed capacitance element Cs is 4 pF, and the capacitance of the second fixed capacitance element Cp is 7.8 pF. The variable capacitance element Cv may be, for example, a MEMS (Micro Electro Mechanical System) variable capacitance element. The capacitance of the variable capacitance element Cv can be controlled by a signal from the controller 5 (see FIG. 1).

In such a configuration, as shown in FIG. 13, the electric length of the non-feeding element 230 is changed by changing the variable capacitance value of the variable capacitance element Cv according to the frequency channel, and the resonance frequency of the non-feeding element 230 is changed. It can be tuned to the frequency channel used (preferably the center frequency of the frequency channel). Thereby, the isolation between the antenna elements can be improved more effectively.

In the example shown in FIG. 13, the variable reactance unit 250 includes the first and second fixed capacitance elements Cs and Cp, but the desired capacitance value can be set accurately only by the variable capacitance element Cv. , These first and second fixed capacitance elements Cs and Cv may not be included. Further, although the variable capacitance element Cv is used as the variable reactance element for adjusting the electric length of the non-feeding element 230, a variable inductor can also be used instead of the variable capacitance element Cv. Further, when the frequency channel is not dynamically assigned to the antenna element (that is, when the frequency channel in which the antenna element is used is fixed), the non-feeding element 230 and the ground are grounded in order to adjust the electric length of the non-feeding element 230. The reactance value of the reactance element connected to the conductor 21 may be a fixed value. By using a reactance element having an appropriate reactance value according to the individual environment in which the non-feeding element 230 is used, the physical length of the non-feeding element 230 is not changed (that is, the non-feeding element 230 having a different physical length is used. The electric length of the non-feeding element 230 can be set to an appropriate length, and the reactance frequency of the non-feeding element 230 can be matched with a desired frequency with high accuracy.

(Fourth Embodiment)
Next, the fourth embodiment will be described. FIG. 14 is a plan view showing the antenna device 6c according to the fourth embodiment.

The antenna device 6c of the fourth embodiment is different from the antenna device 6 of the first embodiment in that it has the second non-feeding element 330, and is the same as the antenna device 6 of the first embodiment in other points. The second non-feeding element 330 is provided to improve the isolation between the first and second antenna elements 10 and 11 in the first frequency band. In particular, the second non-feeding element 330 is configured to reduce the current generated on the first antenna element 10 when the second antenna element 11 is fed at a frequency within the first frequency band.

Like the non-feeding element 30 shown in the first embodiment, the second non-feeding element 330 also has a conductive member arranged apart from the surface of the ground conductor 21 and extending along the surface of the ground conductor 21. It has one end (first end) 331 electrically connected to the ground conductor 21 and an open other end (second end) 332 not connected to the ground conductor 21.

The connection point (second connection point) 340 between the first end portion 331 of the second non-feeding element 330 and the ground conductor 21 extends in a direction intersecting the lower side 22 of the ground conductor 21, and the lower side 22 and the upper side 23 It is arranged at a position closer to the second feeding point 13 than the first feeding point 12 on the left side 24 connecting the above. In other words, the distance D4 from the connection point 340 to the second feeding point 13 is smaller than the distance D3 from the connection point 340 to the first feeding point 12.

The second non-feeding element 330 is also made of a long plate-shaped member, and is bent at the first bent portion 333 and the second bent portion 334. The second non-feeding element 330 includes a first portion 335 extending from the first end portion 331 (that is, the connection point 340) to the first bent portion 333 in a direction away from the surface of the ground conductor 21, and the first bending portion 333. Extends along the surface of the ground conductor 21 in a direction perpendicular to the left side 24 of the ground conductor 21 from the portion 333 (that is, the end of the first portion 335 on the side away from the connection point 340) to the second bent portion 334. The direction from the second portion 336 and the second bent portion 334 (that is, the end of the second portion 336 on the side not connected to the first portion 335) to the second end portion 332 toward the upper side 23 of the ground conductor 21. Has a third portion 337 extending along the surface of the ground conductor 21. As a result, the open second end portion 332 of the second non-feeding element 330 is located closer to the upper side 23 than the first end portion 331 (that is, the connection point 340). Further, the second portion 336 of the second non-feeding element 330 extends substantially parallel to the extending portion of the second antenna element 11 extending along the upper side 23 of the ground conductor 21.

The length from the first end portion 331 to the second end portion 332 of the second passive element 330 corresponds to the representative frequency (for example, the center frequency) of the first frequency band in which the first antenna element 10 is used. It is set to be approximately 1/4 of the wavelength. Therefore, the electric length of the second passive element 330 is approximately 1/4 of the wavelength corresponding to the representative frequency of the first frequency band. As a result, the second non-feeding element 330 resonates in the first frequency band.

Such a second non-feeding element 330 reduces the current generated in the first antenna element 10 via the ground conductor 21 when the second antenna element 11 is fed at a frequency within the first frequency band. , The isolation between the antenna elements 10 and 11 in the first frequency band is improved. In this way, two non-feeding elements can be provided. In the fourth embodiment, the second non-feeding element 330 adapted to improve the isolation between the antenna elements 10 and 11 in the first frequency band is provided, but instead of or in addition to the second non-feeding element 330. , The non-feeding element adapted to improve the isolation between the antenna elements 10 and 11 in the second frequency band or the third frequency band may be provided.

In the above, the embodiment has been described as an example of the technology disclosed in this application. However, the technique in the present disclosure is not limited to this, and can be applied to embodiments in which changes, replacements, additions, omissions, etc. have been made. It is also possible to combine the components described in the above embodiments to form a new embodiment.

For example, in the first embodiment, in order to improve the isolation between the first antenna element 10 and the second antenna element 11 in the second frequency band, the antenna is configured to resonate in the second frequency band. The non-feeding element 30 is provided in the antenna device 6, but instead of or in addition to such a non-feeding element 30, the first antenna element 10 and the first antenna element 10 and the third in the first frequency band or the third frequency band are provided. In order to improve the isolation between the antenna element 2 and the antenna element 11, the antenna device 6 may be provided with a non-feeding element configured to resonate in the first frequency band or the third frequency band.

Further, in the first embodiment, the first wireless system in which the first antenna element 10 is used is a cellular system, and the second wireless system in which the second antenna element 11 is used is an ITS. The wireless system to which the invention can be applied is not limited to these. For example, the wireless system may be a WiFi® system, a Bluetooth® system, or a proprietary system of a specified low power radio station.

Further, in the first embodiment, the second portion 36 and the third portion 37 of the non-feeding element 30 are linear, but these do not necessarily have to be linear and may be bent. Further, the ground conductor 21 does not necessarily have to be a perfect rectangle, and for example, the corners may be rounded. A flat plate-shaped conductor in which the first feeding point of the first antenna element is arranged and a flat plate-shaped conductor in which the second feeding point of the second antenna element is arranged are separately provided, and these two conductors are provided. May be electrically connected to form a single ground conductor.

The antenna device and the electronic device according to the present invention have an effect that the isolation between the antenna elements can be improved without significantly changing the radiation characteristics in the corresponding frequency bands of the plurality of antenna elements, and the plurality of antennas. It is useful as an antenna device having an element and an electronic device equipped with the antenna device.

1 Electronic device 2 Input unit 3 Output unit 4 Memory 5 Controller 6, 6a, 6b, 6c Antenna device 7 Wireless communication unit 8 First feed line 9 Second feed line 10, 110 First antenna element 11, 111 2 Antenna elements 12, 112 1st feeding point 13, 113 2nd feeding point 20 Board 21 Ground conductor 22 Lower side 23 Upper side 24 Left side 30, 130, 230, 330 Non-feeding element (conductive member)
31, 131, 331 First end 32, 132, 332 Second end 33, 133, 333 First bend 34, 134, 334 Second bend 35, 135, 335 First part 36, 136, 336 Second part 37, 137, 337 Third part 40, 140, 340 Connection point 250 Variable reactance part Cs First fixed capacitance element Cv Variable capacitance element Cp Second fixed capacitance element

Claims (11)

Ground conductor and
The first and second feeding points arranged apart from each other on the ground conductor or in the vicinity of the ground conductor,
A first antenna element electrically connected to the first feeding point and used in the first frequency band, and a first antenna element.
A second antenna element electrically connected to the second feeding point and used in a second frequency band different from the first frequency band.
A first end, which is composed of a conductive member arranged apart from the surface of the ground conductor and extends along the surface of the ground conductor and is electrically connected to the ground conductor, and an open second end. A first portion extending from the first end portion in a direction away from the surface of the ground conductor, and a second portion extending along the surface of the ground conductor from the end portion of the first portion on the side away from the first end portion. A non-feeding element having a portion and a third portion extending along the surface of the ground conductor in a direction away from the first antenna element from an end portion of the second portion on the side away from the first portion. Have and
The distance from the connection point between the first end portion of the non-feeding element and the ground conductor to the first feeding point is smaller than the distance from the connecting point to the second feeding point.
The electric length of the non-feeding element is an antenna device in which the non-feeding element resonates in the second frequency band. The antenna device according to claim 1, wherein the electric length of the non-feeding element is set to a length of approximately 1/4 of the wavelength corresponding to the representative frequency of the second frequency band. The antenna device according to claim 1 or 2, wherein the bandwidth of the second frequency band is narrower than the bandwidth of the first frequency band. The ground conductor has a first side and a second side extending from the first side in a direction intersecting the first side.
The antenna device according to any one of claims 1 to 3, wherein the non-feeding element has a portion extending in a direction intersecting the second side of the ground conductor. The first antenna element and the second antenna element are provided in the vicinity, and the first antenna element and the second antenna element are provided in the vicinity.
The antenna device according to claim 1, wherein the third portion extends along the surface of the ground conductor in a direction away from the first antenna element and the second antenna element . The first antenna element is also used in a third frequency band, and the second frequency band is any one of claims 1 to 5 located between the first frequency band and the third frequency band. The antenna device according to paragraph 1. The antenna device according to any one of claims 1 to 6 , wherein the transmission power of the radio wave radiated from the first antenna element is larger than the transmission power of the radio wave radiated from the second antenna element. The antenna device according to any one of claims 1 to 7 , wherein the first end portion of the non-feeding element is connected to the ground conductor via a reactance element. The antenna device according to claim 8 , wherein the reactance element is a variable reactance element. A first end portion that is composed of a conductive member that is arranged apart from the surface of the grounding conductor and extends along the surface of the grounding conductor and is electrically connected to the grounding conductor, and an open second end portion. Further having a second non-feeding element having
The distance from the second connection point, which is the connection point between the first end of the second non-feeding element and the ground conductor, to the second feeding point is the distance from the second connection point to the first. Less than the distance to the feeding point,
The antenna according to any one of claims 1 to 9 , wherein the electric length of the second non-feeding element is set to a length at which the second non-feeding element resonates in the first frequency band. apparatus. The antenna device according to any one of claims 1 to 10.
An electronic device including a wireless communication unit that is electrically connected to the first and second feeding points of the antenna device via the first and second feeding lines and communicates with the outside via the antenna device.

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